Abstract

Introduction

Breast cancer comprises clinically distinct subtypes, but most risk statistics consider
breast cancer only as a single entity. To estimate subtype-specific lifetime breast
cancer risks, we took advantage of population-based data for which information regarding
tumor expression of estrogen receptor (ER), progesterone receptor (PR) and HER2/neu
(HER2) was newly available.

Methods

We included women whose breast cancer was diagnosed in the state of California from
2006 to 2007 and was reported to the National Cancer Institute's Surveillance, Epidemiology
and End Results Program (N = 40,936). We calculated absolute lifetime and age-specific probabilities (percent,
95% confidence interval) of developing breast cancer subtypes defined by ER, PR, and
HER2 status - luminal (ER and/or PR-positive, HER2-negative), HER2-positive (ER and
PR-positive or negative, HER2-positive), and triple-negative (ER-negative, PR-negative,
and HER2-negative) - separately for white, black, Hispanic, and Asian women.

Conclusions

These absolute risk estimates may inform health policy and resource planning across
diverse populations, and can help patients and physicians weigh the probabilities
of developing specific breast cancer subtypes against competing health risks.